Boat propeller mounting and steering mechanism

ABSTRACT

A boat propeller mounting and steering mechanism including an upper housing adapted to be mounted inside the hull of a boat and serving as a mounting and support means for a relatively rotatable lower housing. The lower housing extends through the bottom of the hull, is rotatable about a relatively vertical axis and serves as the rudder as well as the rear mounting means for the propeller shaft and the propeller itself which pivots with the lower housing. The propeller thus exerts a thrust parallel to the bottom of the hull in the direction of desired forward motion and may be located forwardly of the transom such that water is forced into the propeller and it is not subjected to the normal cavitation problem.

United States Patent 1191 Ross [ 1 Nov. 18, 1975 BOAT PROPELLER MOUNTING AND STEERING MECHANISM [75] Inventor: Charles R. Ross, Seattle, Wash.

[73] Assignee: Robertson Ross, Seattle, Wash.

[22] Filed: July 16, 1973 [21] Appl. No.: 379,733

Related U.S. Application Data 3,487,804 l/l97O Kiekhaefer 115/17 Priman E.\'aminer-Trygve M. Blix Assistant ExaminerCharles E. Frankfort Attorney, Agent, or FirmSeed, Berry, Vernon & Baynham [57] ABSTRACT A boat propeller mounting and steering mechanism including an upper housing adapted to be mounted in side the hull of a boat and serving as a mounting and support means for a relatively rotatable lower housing. The lower housing extends through the bottom of the hull, is rotatable about a relatively vertical axis and serves as the rudder as well as the rear mounting means for the propeller shaft and the propeller itself which pivots with the lower housing. The propeller thus exerts a thrust parallel to the bottom of the hull in the direction of desired forward motion and may be located forwardly of the transom such that water is forced into the propeller and it is not subjected to the normal cavitation problem.

2 Claims, 3 Drawing Figures US. Patent Nov. 18, 1975 Sheet2of2 3,919,965

FIG 3 INVENTOR. CHARLES R. ROSS ATTORNEYS BOAT PROPELLER MOUNTING AND STEERING MECHANISM This is a continuation of application Ser. No. 194,706, filed Nov. 1, 1971, and now abandoned.

BACKGROUND OF THE INVENTION The movement of powered boats through the water has continually presented a miriad of problems for the users either in the relative inefficiency of the use of available power or alternatively in the relative expense sacrificed to gain convenience or versatility.

One method which is popular for motivating water borne vehicles, particularly of the pleasure craft line, is the outboard motor wherein the motor itself is pivotally mounted to the upper portion of the transom and has a propeller-rudder combination which extends beneath the water. The direction of the boat is controlled by moving the entire engine with its attached rigid propeller-rudder combination. This type of motivation, as pointed out above, is extremely popular but suffers from the disadvantage that the motor is mounted at the rear of the boat thus placing a great deal of weight to the aft of the boat presenting a load balance problem, also, the outboard motor is by virtue of its placement completely outside the hull more likely to be subjected to damage to the unit including the motor and drive apparatus by impact or the like.

Another means for motivating boats which is popular and widely used is the standard inboard drive wherein an automotive type engine is set within the hull amidships and drives a straight shaft through the bottom of the hull to a propeller which projects beneath the boat. One of the disadvantages of this type of motivation is the fact that because of the relative location of the engine and the propeller the drive shaft and thus the propeller are at an angle to the direction of drive, both sloping slightly downwardly thereby decreasing the efficiency of the thrust generated. Further, with this type of a drive a separate rudder is necessary. The rudder is placed beneath the transom rearwardly of the propellers and is relatively inefficient at slow speeds since there is little water moving by the rudder generating a deflective force.

Yet another method of motivation of boats which is popular and offers some of the advantages of both the inboard and the outboard type drive is that commonly termed inboard-outboard or out drive. An inboard motor drives through a series of gears and prop shafts such that the propeller shaft does not extend through the bottom of the hull but extends through the transom into a gear mechanism which drives a vertical prop shaft which extends down and drives still another shaft in a generally horizontal direction to a propeller. With this combination, the entire unit which extends beneath the water line serves as a propeller mounting device and tiller combination. The fact that the propeller turns with the tiller increases the tiller efficiency. Because of the large amount of gearing necessary this apparatus becomes an expensive item with high maintainance cost.

With the above noted problems in mind it is an object of the present invention to provide a propeller mounting and steering device which greatly increases the efficiency of both units and yet does not require the complex mechanism heretofore required.

Another object of the present invention is to provide a drive and control means for a boat which allows inboard mounting of the engine and a drive through the bottom of the hull and yet permits steering by changing the position of the propeller.

Still another object of the present invention is to place the propeller which drives a boat forward of the transom thus using the bottom of the hull as a surface to prevent cavitation of the propeller.

Still a further object of the present invention is to provide a drive system for a boat which is extremely simple, requires very little maintenance and produces a propeller thrust essentially parallel to the surface of the water.

Yet another object of the present invention is to provide an efficient drive system for a boat and further including a provision for underwater exhaust greatly decreasing the overall noise.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view showing an inventive steering mechanism as seen from the lower front of the boat, the hull being removed for clarity.

FIG. 2 is a rear elevational view, partially in section, of the inventive mechanism showing the internal exhaust ports and assembled installation.

FIG. 3 is a sectional view taken on a plane through the center of the hull showing the relative location of the upper and lower housings as well as the internal exhaust ports.

DETAILED DESCRIPTION OF THE DRAWINGS As can be seen in the Figures, the inventive mechanism includes a generally hollow upper housing 2 including a lower, outwardly extending flange 4 adapted to abut and be affixed to the upper surface of the bottom of the hull. Radially inwardly of the flange 4 is a downwardly depending cylindrical sleeve 6 adapted to extend into and be sealed by the edge of a hole in the bottom of the hull. Secured to the upper housing 2 and extending into its interior as well as extending through the hull is a lower housing 8 adapted to be pivotally secured to the upper housing 2 by a cap screw 10.

The lower housing 8 has an outwardly extending flange 12 at its upper portion adapted to parallel the lower surface of the bottom of the hull and a downwardly projecting elongated generally torpedo shaped, when taken in horizontal cross section, element 14 which terminates in a bulbous cylindrical lower portion 16 adapted to support a propeller shaft 18 for rotary motion therein as explained in greater detail hereinafter.

Aft of the bulbous, generally cylindrical portion 16 of the lower housing is the propeller 20 having a hollow hub 22 and a plurality of blades 23. Forward of the bulbous portion 16 of the propeller shaft 18 projects beyond the housing and is attached to one end of a universal joint 24 which has its other end connected to a drive shaft 26. The drive shaft 26 extends angularly upwardly through the hull of the boat to be given its rotary motion by a conventional engine which will be provided in accord with the purchasers requirements.

Referring now particularly to FIGS. 2 and 3 in combination where the device is shown installed upon a boat hull, it can be seen that the inventive mechanism is adapted to be mounted such that it extends through the bottom 40 of the hull of the boat. The upper housing 2 is secured to the upper surface of the bottom of the hull by means of a plurality of lag screws 42 extending through the flange 4 and then into the hull itself. In addition to the flange 4 theupper housing includes a generally downwardly extending sleeve 6 which is of a cylindrical configuration to tightly fit against the edge of the hole in the hull and is sealed thereto. The flange 6 has a cylindrical inner surface to allow rotational movement of the upwardly extending neck of the lower housing therein. Extending upwardly from the flange 4 is themain housing of a hollow truncated conical shape and having a bore 44 centrally located in the flat upper surface. The exterior of the housing includes as an integral portion, a plurality of web members 46 for increased strength.

Further, as best seen in FIGS. 1 and 2, the upper housing includes ports 48 through its exterior shell adapted to receive conduits from the engine thereby carrying the exhaust from the engine into the center of the upper housing for transfer through the lower housing and eventually released below the water level.

The lower housing 8 is hollow, similar to the upper housing, and in communication therewith and includes an upwardly extending neck 50 having an outer cylindrical surface of a size to rotationally fit within the downwardly extending flange 6 of the upper housing. Between the neck 50 of the lower housing and the downwardly extending flange 6 of the upper housing there is a wear sleeve 52 for reasons well known in the art. Extending upwardly from the top of the neck 50 is a rigid member of a generally truncated conical shape conforming tothe shape of the upper housing 2, said rigid member being made of a plurality of diagonally placed structural web elements 54 extending from the top of the neck and terminating in a collar 56. Extending upwardly from the collar 56 is a shaft 58 having a threaded end adapted to receive the cap screw 10. In assembly the space between the top part of the collar 56 as well as between the shaft 58 and thebore 44 is filled with a flange type bushing 60 preferably of an easy slip variety. Mounted on top of the flange bushing 60 is an O-ring 62 and spacers 64 as needed to adjust for varying thickness in the boat hull. A tiller arm or quadrant 66 is secured to the upper portion of shaft 58, said tiller arm being secured in position by the cap screw 10. Angular movement of the tiller arm will result in angular movement of the entire lower housing.

Proceeding downwardly beneath the hull, it can'be seen in FIG. 3 that the neck portion 50, which extends upwardly within the sleeve 6, is integrally connected with the main lower housing '14 which is, as noted above, a general torpedo shape in horizontal cross section and is hollow. The torpedo shape of the exterior of the lower housing permits it to pass through the water with little resistance and the side surfaces, because of the vertical dimension in combination with the length, are large enough to produce a side thrust when placed at an angle to the direction of travel thus serving as a liner 88 spacedly located from the shaft by a plurality of bearing members 90. The afterend of the propeller shaft 80 is of a reduced cross section as seen at 92 and extends outwardly of the housing 16 per se. The aft end of the shaft 80 is secured to the housing similarly to the connection at the front of the housing 16. The shaft connection includes a thrust washer 94, a wear spacer 96 and a thrust block 98. The propeller 20 is itself secured to a hollow hub 22 which, as can be seen in FIG. 2 includes a plurality of web members 100 thus providing a through flow for the exhaust gas as described hereinafter. The propeller is secured to the shaft by a lock collar 102, a lock washer 104 and propeller nut 106. A trim tab is pivotally secured to the after portion of lower housing 8 and compensates for the side thrust generated by the turning propellers. The trim tab 120 may be constructed of a zinc substance serving as an anode for the electrolite reaction of differing metals. The use of a trim tab of zinc has a further advantage in that when the anode has been substantially reduced in size the boat will not handle properly indicating the need for anode replacement.

It can thus be seen that no only does the present combination provide more accurate and stable steering for the boat when in use, because of the fact that, both the propeller and the lower housing pivot thus providing additional resistance to the water but further the propeller is mounted beneath the hull forward of the transom thus preventing cavitation. In addition to the above, the exhaust from the engine is channeled beneath the water greatly reducing the noise factor.'The exhaust, as noted above, is fed into ports 48 in the upper housing passes between the web members 54 in the lower housing into the large hollow interior of the lower housing and then outwardly through the bulbous lower portion 16 to be exhausted through the propeller hub 22. The combination thus provides a more soundproof exhaust by porting it under water and further the movement of the boat through the water causes a slight vacuum within the lower chamber greatly increasing the efficiency of the exhaust.

The use of the lower housing and propeller combination eliminates the need for a separate rudder thus allowing the propeller to be positioned forward of the transom, eliminating propeller noise and preventing cavitation since the bottom of the boat is used as a cavitation plate. The ability to locate the propeller shaft parallel to the bottom of the boat makes the entire system extremely more efficient since the thrust of the propeller is in the direction of the desired movement and further this combination allows the boat to be steered in reverse as well as making the entire boat more maneuverable.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A boat propeller mounting device wherein the propeller rotates about a first axis generating thrust urging the boat in adirection of desired travel and a portion of the mounting device pivots about a vertical axis for steering the boat, said mounting device comprising:

an elongated, hollow lower housing adapted to be positioned below the bottom portion of the boat hull and having an upper portion thereof extending upwardly through the hull, a propeller shaft positioned in and extending from the lower portion of said lower housing at opposite ends thereof, a propeller mounted on the rearward end of said shaft,

and an exhaust exit port allowing communication the hollow interiors of said upper and lower housbetween the interior and exterior of said lower ings and out said exit port; and

housing; propeller driving means positioned within the hull a hollow upper housing secured within the interior of and connecting means extending from the propelthe hull and means pivotally securing said upper 5 ler driving means and joined to the forward end of portion of the lower housing within said hollow the propeller shaft by a universal joint positioned upper housing, an opening in the top of said upper below the bottom of the hull in line with the pivot housing and extension means on the upper portion axis of said lower housing.

of the lower housing extending through and above 2. A boat propeller mounting device as in claim 1 said opening, steering control means secured to the 10 wherein said upper housing includes a cylindrical porextension means at a point above the upper houstion extending through the hull of said boat and ing and providing means for pivoting the lower adapted to receive a cylindrical portion of said lower housing relative to the upper housing, and an exhousing passing through said hull. haust inlet port for allowing exhaust gas flow into 

1. A boat propeller mounting device wherein the propeller rotates about a first axis generating thrust urging the boat in a direction of desired travel and a portion of the mounting device pivots about a vertical axis for steering the boat, said mounting device comprising: an elongated, hollow lower housing adapted to be positioned below the bottom portion of the boat hull and having an upper portion thereof extending upwardly through the hull, a propeller shaft positioned in and extending from the lower portion of said lower housing at opposite ends thereof, a propeller mounted on the rearward end of said shaft, and an exhaust exit port allowing communication between the interior and exterior of said lower housing; a hollow upper housing secured within the interior of the hull and means pivotally securing said upper portion of the lower housing within said hollow upper housing, an opening in the top of said upper housing and extension means on the upper portion of the lower housing extending through and above said opening, steering control means secured to the extension means at a point above the upper housing and providing means for pivoting the lower housing relative to the upper housing, and an exhaust inlet port for allowing exhaust gas flow into the hollow interiors of said upper and lower housings and out said exit port; and propeller driving means positioned within the hull and connecting means extending from the propeller driving means and joined to the forward end of the propeller shaft by a universal joint positioned below the bottom of the hull in line with the pivot axis of said lower housing.
 2. A boat propeller mounting device as in claim 1 wherein said upper housing includes a cylindrical portion extending through the hull of said boat and adapted to receive a cylindrical portion of said lower housing passing through said hull. 